Modeling subduction earthquake sources in the central-western region of Colombia using waveform inversion of body waves

Monsalve-Jaramillo, Hugo; Valencia-Mina, William; Cano-Saldaña, Leonardo; Vargas, Carlos

doi:10.1016/j.jog.2018.02.005

Cited by 3 publications

(2 citation statements)

References 25 publications

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“…In the last 15 years, the number of ambient noise tomography (ANT) studies has increased dramatically. They have been applied to geology characterization (Picozzi et al, 2009;Chavez-Garcia, and Raptakis, 2016;Kil et al, 2021), exploration of geothermal resources (Lehujeur et al, 2021;Ozer et al, 2022), geothermal monitoring (Obermann et al, 2015) and tectonic/fault mapping (Nicolson et al, 2012;Li and Lin, 2014;Brandmayr et al, 2016;Cubuk-Sabuncu et al, 2017;Monsalve-Jaramillo et al, 2018;Schippkus et al, 2018;Sahin et al, 2019;Zulfakriza et al, 2020;Cardenas-Soto et al, 2021;Zhang et al, 2022;Turunctur et al, 2023). The present development of broadband arrays in western Anatolia gives an opportunity to apply ANT to the determination of the crustal structure of this region.…”

Section: Introductionmentioning

confidence: 99%

Ambient noise tomography of the Aegean region of Türkiye from Rayleigh wave group velocity

Mulumulu,

Polat,

Chávez-García

2023

Front. Earth Sci.

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We have studied Rayleigh wave group velocities beneath the Aegean region of Türkiye using ambient noise tomography. Noise data were gathered from 43 broadband seismic stations belonging to three permanent broad-band arrays. The cross-correlation method was used to estimate empirical Green’s functions. Group velocities of the fundamental mode Rayleigh waves were determined using multiple filter technique. We measured dispersion for each station pair in a period range of 2–12 s and computed maps of group velocity distribution using the fast marching surface tomography method. The group velocity maps correlate well with the geological and tectonic features of the region, displaying low velocities for the Quaternary alluvial basins, moderate velocities for Cretaceous rocks, and high velocities for the regions where gneiss and granitoid rocks outcrop. Low velocity anomalies may be associated with the grabens and horsts formed by faulting and to deep mantle flow. We detect potential offshore geothermal zones in Izmir and Candarli Bay. The information from broad-band networks improves the resolution of crustal surface wave velocity structures, particularly for shallow depths. This improvement will support the assessment of seismic hazard, as the shallow layers of the crust contribute significantly to seismic activity.

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Section: Introductionmentioning

confidence: 99%

Ambient noise tomography of the Aegean region of Türkiye from Rayleigh wave group velocity

Mulumulu,

Polat,

Chávez-García

2023

Front. Earth Sci.

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“…In this region, the global centroid moment tensor catalog (Dziewonski et al, ; Ekström et al, ) shows strike‐slip, normal, and reverse faulting earthquakes with 4.9 ≤ M W ≤ 7.0 (Figure ). Monsalve‐Jaramillo et al () also observed similarly variable focal mechanisms for four large earthquakes in the cluster. Analysis of centroid moment tensor focal mechanisms from 1976 to 2002 in combination with focal mechanisms of additional earthquakes of similar magnitudes collected by Cortés and Angelier (; Figure S1 in the supporting information) or alone has shown that the extensional stress axis is located in the plane of the slab, either in the downdip direction (dipping at 33° toward N98°E) (Cortés & Angelier, ) or rotated ~45° from the downdip direction (Chen et al, ).…”

Section: Introductionmentioning

confidence: 66%

Earthquake Focal Mechanisms and Stress Field for the Intermediate‐Depth Cauca Cluster, Colombia

et al. 2019

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Beneath southwestern Colombia, intermediate-depth earthquakes in the Cauca cluster locate in the subducting Nazca plate and in two columns extending~40-km into the mantle wedge above the slab. To investigate the cluster, we determine focal mechanisms for 69 small-to-moderate-sized (2.3 ≤ Ml ≤ 4.7) earthquakes in the cluster by fitting short-period body wave waveforms using the cut-and-paste method. The focal mechanisms have various faulting types and variably oriented nodal planes. We invert the focal mechanisms of the intraslab earthquakes for the intraslab stress field but cannot fit the region with a homogeneous stress tensor. We find that the principal stress axes rotate with the slab geometry, which has a concave shape and increases in dip angle from north to south. The northern region has slab normal compression and similar-magnitude maximum and intermediate principal stresses. The minimum stress axis is oriented~41°c ounterclockwise from the downdip direction. In the steeper southern region, the intermediate stress axis orients in the downdip direction. Deviation from a typical downdip extensional stress field may result from a buoyant young slab, an eastward mantle flow push, and/or along-strike compression from the concave shape of the slab. This stress field would allow slip along preexisting faults of various orientations, such as the trench-perpendicular seafloor features presently observed offshore, and contribute to the apparent heterogeneity of the intraslab stress field. The mantle wedge earthquakes also have various focal mechanisms but tend to have a subvertical nodal plane that aligns with the earthquake locations.

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Recognition of seismogenic sources using time-frequency analysis

Buitrago

Saldaña

Monsalve

2023

Preprint

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A characterization of seismic signals was carried out, using signal analysis techniques in the time-frequency domain, in order to identify the relevant characteristics of five seismic sources, excluding any knowledge of the seismogenic source and extracting and recognizing characteristic patterns that would allow classification of the earthquakes and to allow any possible qualitative explanation of a likely source that originated the event. For this purpose, a database consisting of 293 signals that were previously located and assigned to mentioned seismic sources. Finally, a basic classification system was designed through a neural network multilayer perceptron that assigns the earthquake to one of the seismic sources established according to the features and patterns that have been detected using time-frequency analysis.

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Modeling subduction earthquake sources in the central-western region of Colombia using waveform inversion of body waves

Cited by 3 publications

References 25 publications

Ambient noise tomography of the Aegean region of Türkiye from Rayleigh wave group velocity

Ambient noise tomography of the Aegean region of Türkiye from Rayleigh wave group velocity

Earthquake Focal Mechanisms and Stress Field for the Intermediate‐Depth Cauca Cluster, Colombia

Recognition of seismogenic sources using time-frequency analysis

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